(a) Field of the Invention
The present invention relates to a caster braking structure, and more particularly, to one that executes braking to the caster and prevent it from turning by having a longitudinal slide linkage to indirectly drive two retaining elements to move laterally and respectively stop the caster and a vertical shaft.
(b) Description of the Prior Art
The present invention is a further improvement of application Ser. No. 09/754056 filed on Jan. 5, 2001. The prior art is essentially designed to have a single latching element to drive two laterally moving retaining members while applying braking to the caster and its vertical shaft, thus to stop and hold the caster from turning it direction. In the configuration of its physical structure, a horizontal accommodation trough is laterally formed in the flush side of a semi-spherical bottom of the caster holder. One end of the accommodation trough is formed upwardly a recess connecting through a vertically provided shaft mouth to receive the insertion of the shaft; a slot is upwardly formed in the shaft mouth relatively to the trough for the shaft and the slot to define a protrusion ring containing a positioning dent. A latching piece is pivoted at the other end of the trough with its pivoting portion formed a block with a distal and a proximal end in relation to the pivoting center. A laterally moving slider holder is provided in the trough and is constantly holding against the pivoting portion of the latching piece for being subject to the push by a flexible member. A cut is formed at the lower end where the push by the flexible member takes place so to facilitate turning the pivoting portion of the latching piece. At the other end a fixation pin is inserted through and extending further to rest in a long slot provided in the caster holder so to merely for the fixation pin to contact the circular groove formed on the inner side of the caster holder while at the same end of the slider holder is placed into a retaining block abutted to the groove. The retaining block being subject to the push by another flexible member holds against that end of the slider holder, and moves together with the lateral movement of the slider holder into the positioning dent disposed at the circular protrusion of the shaft in the slot to be held in position. Once the latching piece is depressed to apply double braking, the pivoting portion turns to have its distal end pushing into the slider holder for the fixation pin to extend and hold against the groove on the inner side of the caster to the apply brake to the caster. The retaining block as pushed by the flexible member advances together with the slider holder into the positioning dent in the circular protrusion of the shaft to prevent the caster from turning in any direction.
However, in exploring for a more practical design than the prior art, the latching piece must be provided on the side of the caster holder where the latching piece protrudes on the bias to form a xe2x80x9claterally protruding objectxe2x80x9d since in the configuration of the prior art, it is directly turned by means of the lacking piece to having the distal end of its pivoting portion to push the slider holder for the linked retaining members to execute double braking. Though the braking performance is not affected, such planning is detrimental to the appearance of the caster and such protruding object can easily trip the passer-by and a further improvement is justified.
The primary purpose of the present invention is to provide a caster braking and locking structure to have the latching piece (referred as a press button in the present invention) incorporated to the caster to be disposed at an appropriate location without excessive protrusion, and to have the latching piece indirectly driven via linkage of a longitudinally provided slider for both retaining members to synchronously execute lateral movement to respectively stop and lock characterized by that:
a vertically provided chute is formed over one side of the horizontal trough of the caster holder that contains the slider holder for the placement wherein a longitudinally provide slider. The lower end of the slider is connected to one end of the slider holder to define a slope and a pivoting recess if formed in the upper of the biased side of the caster holder, which connects the vertically provided chute. In the pivoting recess, a press button is relatively pivoted with its circular pivot. A wing is provided to the outer end of the circular pivot for depression. The circular pivot in relation to the upper end of the longitudinally provided slider is pushed and held in position by a retaining surface so the slider is pushed to move downward. Furthermore, the slop on the lower end of the slider pushes against that provided on the end of the slider holder for it to execute lateral movement together with the retaining block provided on the slider holder thus to apply brake to and prevent the caster from turning in any direction.